Communication device and communication method

ABSTRACT

Disclosed is a wireless communication base station device capable of reducing the power consumption of a terminal when broadband transmission is performed with only an uplink. With this device, a setting unit sets mutually different terminal IDs per a plurality of uplink unit bands for a terminal that communicates using a plurality of uplink unit bands and prescribed downlink unit bands which are fewer in number than the uplink unit bands; a control unit that respectively allocates resource allocation information per a plurality of uplink unit bands to a PDCCH arranged in a prescribed downlink unit band; and a PDCCH creation unit that creates a PDCCH signal by respectively masking the resource allocation information per a plurality of uplink unit bands with the terminal ID that has been set per a plurality of uplink unit bands.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. application Ser. No.16/030,101, filed Jul. 9, 2018, which is a continuation application ofU.S. application Ser. No. 15/271,899, filed Sep. 21, 2016, which is acontinuation application of U.S. application Ser. No. 14/035,193 filedSep. 24, 2013, which is a continuation application of U.S. applicationSer. No. 13/058,151 filed Feb. 8, 2011, which is a 371 application ofPCT/JP2009/003841 filed Aug. 10, 2009, which is based on JapaneseApplication No. 2008-207369 filed Aug. 11, 2008, the entire contents ofeach of which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a radio communication base stationapparatus, a radio communication terminal apparatus and a controlinformation generating method.

BACKGROUND ART

3GPP-LTE (3rd Generation Partnership Project Radio Access Network LongTerm Evolution) adopts OFDMA (Orthogonal Frequency Division MultipleAccess) as a downlink communication scheme, and SC-FDMA (Single CarrierFrequency Division Multiple Access) as an uplink communication scheme(for example, see Non-Patent Literatures 1, 2 and 3.)

With LTE, a radio communication base station apparatus (hereinafterabbreviated as “base station”) communicates with radio communicationterminal apparatuses (hereinafter abbreviated as “terminals”) byassigning resource blocks (RBs) in the system band to terminals, pertime unit referred to as subframe. In addition, a base station transmitscontrol information to notify, to terminals, the result of assignment ofresources for downlink data and uplink data.

This control information is transmitted to terminals using downlinkcontrol channels, for example, PDCCHs (physical downlink controlchannels.) Here, LTE supports a frequency band having the maximum widthof 20 MHz as the system bandwidth.

In addition, a base station transmits a plurality of PDCCHs at the sametime to assign a plurality of terminals to one subframe. At this time,the base station transmits a PDCCH including CRC bits masked (scrambled)with a destination terminal ID to identify each PDCCH destinationterminal. Then, a terminal performs blind-decoding on a plurality ofPDCCHs which may be directed to the terminal by demasking (ordescrambling) CRC bits in the plurality of PDCCHs, with its terminal IDto detect the PDCCH directed to the terminal.

In addition, standardization of 3GPP LTE-Advanced that realizes fastercommunication than by LTE has been started. With LTE-Advanced, in orderto realize a downlink transmission speed equal to or higher than themaximum 1 Gbps and an uplink transmission speed equal to or higher thanthe maximum 500 Mbps, base stations and terminals (hereinafter “LTE+terminals”) that are able to communicate with each other at a widebandfrequency equal to or higher than 40 MHz, will be employed. In addition,an LTE-Advanced system is required to accommodate not only LTE+terminals but also terminals (hereinafter “LTE terminals”) supporting anLTE system.

In addition, with LTE-Advanced, a band aggregation scheme forcommunication by connecting a plurality of frequency bands, is proposed.Here, a base unit of communication bands (hereinafter “component bands”)is a frequency band having a width of 20 MHz. Therefore, LTE-Advancedrealizes a system bandwidth of 40 MHz by connecting two component bands.

In addition, with LTE-Advanced, studies are underway to associatecomponent bands in the uplink (hereinafter “uplink component bands”)with component bands in the downlink (hereinafter “downlink componentbands”) one by one (e.g. Non-Patent Literature 4.) That is, a basestation notifies resource assignment information about each componentband to terminals using the downlink component band in each componentband. For example, a terminal that performs transmission in a widebandof 40 MHz (terminal using two component bands) acquires resourceassignment information about two component bands by receiving PDCCHsallocated to the downlink component band in each component band.Therefore, in an LTE-Advanced system, a base station can notify resourceassignment information per component band, to terminals in both caseswhere one component band is used (for example, in a case ofcommunication with LTE terminals supporting a band of 20 MHz), and wherea plurality of component bands are used (for example, in a case ofcommunication with LTE+ terminals supporting a band of 40 MHz.) That is,a base station can use the same notifying method between LTE terminalsand LTE+ terminals, so that it is possible to construct a simple system.

CITATION LIST Non-Patent Literature

[NPL 1] 3GPP TS 36.211 V8.3.0, “Physical Channels and Modulation(Release 8),” May 2008

[NPL 2] 3GPP TS 36.212 V8.3.0, “Multiplexing and channel coding (Release8),” May 2008

[NPL 3] 3GPP TS 36.213 V8.3.0, “Physical layer procedures (Release 8),”May 2008

[NPL 4] 3GPP TSG RAN WG1 meeting, R1-082468, “Carrier aggregationLTE-Advanced,” July 2008

SUMMARY OF INVENTION Technical Problem

In a terminal, when a frequency bandwidth of received signals is wider,power consumption increases. Therefore, power consumption of a terminalthat performs wideband transmission (for example, communication band of40 MHz) is greater than that of a terminal that performs narrowbandcommunication (for example, communication band of 20 MHz.) Therefore,minimization of power consumption of a terminal is possible byadaptively controlling the number of component bands to be connected,according to the transmission amount (or transmission speed) of data.

To be more specific, when the amount of transmission data is greater,the number of component bands to be connected increases.

Here, with LTE-Advanced, it is expected that the amount of transmissiondata in the uplink and the amount of transmission data in the downlinkare independent of one another. For example, there may be a case wherewideband transmission (in a communication band of 40 MHz) is performedin the uplink while narrowband transmission (in a communication band of20 MHz) is performed in the downlink. That is, there may be a casewhere, for example, two uplink component bands are used in the uplinkand only one downlink component band is used in the downlink.

However, with the above-described prior art, uplink component bands areassociated with downlink component bands one by one. That is, resourceassignment information indicating resources in an uplink component bandto assign uplink data from a terminal to, is notified using the downlinkcomponent band associated with that uplink component band. Therefore,even if wideband transmission (for example, in a communication band of40 MHz) is performed only in the uplink, that is, even if both theuplink component band and the downlink component band are used in one oftwo component bands used by a terminal while only the uplink componentband is used in the other component band, the terminal has to receivePDCCHs using the downlink component bands associated with respectiveuplink component bands to notify resource assignment information abouteach uplink component band.

For example, a case in which a terminal uses two component bands(component band 1 and component band 2) will be explained. When widebandtransmission (for example, in a communication band of 40 MHz) isperformed only in the uplink, a terminal uses, for example, uplinkcomponent bands in both component band 1 and component band 2.Meanwhile, in the downlink, the terminal performs narrowbandtransmission (for example, in a communication band of 20 MHz) by usingonly the downlink component band in component band 1, not using thedownlink component band in component band 2. Here, the terminal has toreceive uplink resource assignment information indicating assignment ofresources in the uplink component band in component band 2, using PDCCHsallocated to the downlink component band in component band 2. Therefore,although the terminal does not use the downlink component band incomponent band 2 for data transmission, the terminal needs to receivePDCCHs allocated to the downlink component band in component band 2.

That is, although narrowband transmission (for example, in acommunication band of 20 MHz) is performed in the downlink, a terminalneeds to receive wideband signals (for example, signals in acommunication band of 40 MHz) even in the downlink, and consequently,power consumption of the terminal increases.

It is therefore an object of the present invention to provide a basestation, a terminal and a control information generating method toreduce power consumption of terminals even if wideband transmission isperformed only in the uplink.

Solution to Problem

The base station according to the present invention adopts aconfiguration to include: a configuration section that configuresvarying terminal IDs between a plurality of uplink component bands, fora radio communication terminal apparatus that performs communicationusing the plurality of uplink component bands and a smaller number ofspecific downlink component bands than a number of the plurality ofuplink component bands; a control section that assigns resourceassignment information about each of the plurality of uplink componentbands, to control channels allocated to a specific downlink componentband; and a generating section that generates control information bymasking the resource assignment information about each of the pluralityof uplink component bands, with a terminal ID configured for each of theplurality of uplink component band.

The terminal according to the present invention that performscommunication using a plurality of uplink component bands and a smallernumber of specific downlink component bands than a number of theplurality of uplink component bands adopts a configuration to include: ablind-decoding section that obtains resource assignment informationabout each of the plurality of uplink component bands, which is directedto the radio communication terminal apparatus, by demasking controlchannels allocated to a specific downlink component band, with terminalIDs respectively configured for the plurality of uplink component bands;and a mapping section that maps uplink data to the plurality of uplinkcomponent bands, according to the resource assignment information abouteach of the plurality of uplink component bands.

The control information generating method according to the presentinvention includes: configuring varying terminal IDs between a pluralityof uplink component bands, for a radio communication terminal apparatusthat performs communication using the plurality of uplink componentbands and a smaller number of specific downlink component bands than anumber of the plurality of uplink component bands; controlling to assignresource allocation information about each of the plurality of uplinkcomponent bands, to control channels allocated to a specific downlinkcomponent band; and generating control information by masking theresource assignment information about each of the plurality of uplinkcomponent bands, with a terminal ID configured for each of the pluralityof uplink component bands.

Advantageous Effects of Invention

According to the present invention, even if wideband transmission isperformed only in the uplink, it is possible to reduce power consumptionof terminals.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of a base stationaccording to Embodiment 1 of the present invention;

FIG. 2 is a block diagram showing a configuration of a terminalaccording to Embodiment 1 of the present invention;

FIG. 3 shows configuration of terminal IDs according to Embodiment 1 ofthe present invention;

FIG. 4 shows configuration of terminal IDs according to Embodiment 1 ofthe present invention;

FIG. 5 shows an example of component bands and terminal IDs configuredfor each terminal according to Embodiment 1 of the present invention;

FIG. 6 shows configuration of terminal IDs according to Embodiment 2 ofthe present invention;

FIG. 7 shows configuration of terminal IDs according to Embodiment 2 ofthe present invention;

FIG. 8 shows configuration of terminal IDs according to Embodiment 3 ofthe present invention;

FIG. 9 shows configuration of terminal IDs according to Embodiment 3 ofthe present invention;

FIG. 10 is a sequence diagram showing processing to configure terminalIDs according to Embodiment 3 of the present invention;

FIG. 11 shows processing to create a temporary terminal ID according toEmbodiment 4 of the present invention;

FIG. 12 shows configuration of terminal IDs according to Embodiment 4 ofthe present invention;

FIG. 13 shows configuration of search spaces according to Embodiment 5of the present invention;

FIG. 14 shows configuration of search spaces according to Embodiment 5of the present invention; and

FIG. 15 shows another configuration of terminal IDs according to thepresent invention.

DESCRIPTION OF EMBODIMENTS

Now, embodiments of the present invention will be described in detailwith reference to the accompanying drawings. Here, in embodiments, thesame components are assigned the same reference numerals and overlappingdescriptions will be omitted.

Embodiment 1

FIG. 1 is a block diagram showing a configuration of base station 100according to the present embodiment.

In base station 100 shown in FIG. 1, configuration section 101configures one or more component bands used in the uplink and thedownlink, per terminal, for example, according to a requiredtransmission rate or transmission amount of data. In addition,configuration section 101 configures varying terminal IDs betweencomponent bands, for each terminal. To be more specific, configurationsection 101 configures different terminal IDs for a plurality ofcomponent bands, respectively, where one uplink component band and onedownlink component band are associated with one another in a componentband, and either an uplink component band or a downlink component bandis configured for a terminal. Then, configuration section 101 outputsconfiguration information indicating component bands configured for eachterminal and terminal IDs configured for respective component bands, tocontrol section 102, PDCCH generating section 103 and modulation section105.

Control section 102 generates uplink resource assignment informationindicating uplink resources (e.g. PUSCHs (physical uplink sharedchannels)) to assign uplink data from terminals to, and generatesdownlink resource assignment information indicating downlink resources(e.g. PDSCHs (physical downlink shared channels)) to assign downlinkdata directed to terminals to. Then, control section 102 outputs uplinkresource assignment information to PDCCH generating section 103 andextracting section 115, and outputs downlink resource assignmentinformation to PDCCH generating section 103 and multiplexing section107. Here, control section 102 assigns uplink resource assignmentinformation and downlink resource assignment information to PDCCHsallocated to downlink component bands configured for respectiveterminals, based on configuration information inputted fromconfiguration section 101. To be more specific, control section 102assigns downlink resource assignment information to PDCCHs allocated tothe downlink component band that is targeted for resource assignment andindicated by the downlink resource assignment information. In addition,control section 102 assigns uplink resource assignment information toPDCCHs allocated to the downlink component band associated with theuplink component band that is targeted for resource assignment andindicated by the uplink resource assignment information. Here, when nodownlink component band associated with the uplink component band thatis targeted for resource assignment and indicated by uplink resourceassignment information, is configured for a terminal, control section102 assigns uplink resource assignment information to PDCCHs allocatedto a specific downlink component band, among downlink component bandsconfigured for the terminal, which is closest to the downlink componentband associated with the uplink component band that is targeted forresource assignment and indicated by the uplink resource assignmentinformation. Here, assignment control processing in control section 102will be described in detail later.

PDCCH generating section 103 generates PDCCH signals including uplinkresource assignment information and downlink resource assignmentinformation inputted from control section 102. In addition, PDCCHgenerating section 103 adds CRC bits to PDCCH signals to which uplinkresource assignment information and downlink resource assignmentinformation are assigned, and masks (or scrambles) the CRC bits withterminal IDs. Here, PDCCH generating section 103 masks CRC bits added toeach resource assignment information, with the terminal ID configuredper component band that is targeted for resource assignment andindicated by each resource assignment information. Then, PDCCHgenerating section 103 outputs a PDCCH signal after masking tomodulation section 104.

After channel coding, modulation section 104 modulates the PDCCH signalinputted from PDCCH generating section 103 and outputs a PDCCH signalafter modulation to multiplexing section 107.

Modulation section 105 modulates configuration information inputted fromconfiguration section 101 and outputs configuration information aftermodulation to multiplexing section 107.

After channel coding, modulation section 106 modulates inputtedtransmission data (downlink data) and outputs a transmission data signalafter modulation to multiplexing section 107.

Multiplexing section 107 multiplexes a PDCCH signal inputted frommodulation section 104, configuration information inputted frommodulation section 105 and a data signal (i.e. PDSCH signal) inputtedfrom modulation section 106. Here, multiplexing section 107 maps thePDCCH signal and data signal (PDSCH signal) to each downlink componentband, based on downlink resource assignment information inputted fromcontrol section 102. Here, multiplexing section 107 may mapconfiguration information to PDSCHs.

IFFT (inverse fast Fourier transform) section 108 transforms amultiplexed signal to a time domain waveform, and CP (cyclic prefix)adding section 109 adds a CP to this time domain waveform to obtain anOFDM signal.

Transmission RF section 110 applies transmission radio processing(up-conversion, digital-to-analog (D/A) conversion and so forth) to theOFDM signal inputted from CP adding section 109, and transmits theresult via antenna 111.

Meanwhile, reception RF section 112 applies reception radio processing(down-conversion, analog-to-digital (A/D) conversion and so forth) to areception radio signal received in a reception band via antenna 111, andoutputs a resulting reception signal to CP removing section 113.

CP removing section 113 removes a CP from a received signal, and FFT(inverse fast Fourier transform) section 114 transforms a receivedsignal without a CP to a frequency domain signal.

Extracting section 115 extracts uplink data from the frequency domainsignal inputted from FFT section 114, based on uplink resourceassignment information inputted from control section 102. IDFT (inversediscrete Fourier transform) section 116 transforms an extracted signalto a time domain signal and outputs the time domain signal to datareceiving section 117.

Data receiving section 117 decodes the time domain signal inputted fromIDFT section 116. Then, data receiving section 117 outputs uplink dataafter decoding as received data.

FIG. 2 is a block diagram showing a configuration of terminal 200according to the present embodiment. Terminal 200 is able to performcommunication, using a plurality of uplink component bands and a smallernumber of specific downlink component bands than the number of theplurality of uplink component bands.

In terminal 200 shown in FIG. 2, reception RF section 202 is formed witha reception band which can be changed, and changes its reception bandbased on band information inputted from configuration informationreceiving section 206. Then, reception RF section 202 applies receptionradio processing (down-conversion, analog-to-digital (A/D) conversionand so forth) to a reception radio signal (OFDM signal here) received inthe reception band via antenna 201, and outputs a resulting receivedsignal to CP removing section 203.

CP removing section 203 removes a CP from the received signal, and FFTsection 204 transforms a received signal without a CP to a frequencydomain signal. This frequency domain signal is outputted todemultiplexing section 205.

Demultiplexing section 205 demultiplexes the signal inputted from FFTsection 204 into a high-layer control signal (e.g. RRC signaling)including configuration information, a PDCCH signal and a data signal(i.e. PDSCH signal.) Then, demultiplexing section 205 outputs controlinformation to configuration information receiving section 206, outputsa PDCCH signal to PDCCH receiving section 207, and outputs a PDSCHsignal to PDSCH receiving section 208.

Configuration information receiving section 206 reads informationindicating uplink component bands and downlink component bandsconfigured for terminal 200, from a control signal inputted fromdemultiplexing section 205, and outputs the read information to PDCCHreceiving section 207, reception RF section 202 and transmission RFsection 214, as band information. In addition, configuration informationreceiving section 206 reads information indicating respective terminalIDs of component bands, which are configured for terminal 200, from acontrol signal inputted from demultiplexing section 205, and outputs theread information to PDCCH receiving section 207, as terminal IDinformation.

PDCCH receiving section 207 performs blind-decoding on a PDCCH signalinputted from demultiplexing section 205. Here, PDCCH signals areallocated downlink component bands, respectively, which are configuredfor terminal 200 and indicated by band information inputted fromconfiguration information receiving section 206. PDCCH receiving section207 demodulates and decodes a PDCCH signal inputted from demultiplexingsection 205, and, when a PDCCH signal after decoding indicates thatCRC=OK (there is no error) by demasking CRC bits with terminal IDs ofterminal 200 indicated by terminal ID information inputted fromconfiguration information receiving section 206, determines the PDCCHsignal is directed to terminal 200. Here, when a plurality of componentbands are configured for terminal 200, varying terminal IDs betweencomponent bands are assigned. PDCCH receiving section 207 acquiresresource assignment information about a subject component band byperforming the above blind-decoding using respective terminal IDs ofcomponent bands to transmit PDCCH signals. In addition, when an uplinkcomponent band in which the associated downlink component band is notconfigured (unconfigured) is configured in terminal 200, PDCCH receivingsection 207 performs blind-decoding on the PDCCH allocated to thespecific downlink component band closest to the downlink component bandassociated with that uplink component band, with the terminal IDconfigured for that uplink component band. That is, PDCCH receivingsection 207 determines resource assignment information obtained bydemasking the terminal ID configured per component band, as resourceassignment information for the component band. Then, PDCCH receivingsection 207 outputs downlink resource assignment information included inthe PDCCH signal directed to terminal 200, to PDSCH receiving section208, and outputs uplink resource assignment information to frequencymapping section 211.

PDSCH receiving section 208 extracts received data from a PDSCH signalinputted from demultiplexing section 205, based on the downlink resourceassignment information inputted from PDCCH receiving section 207.

Modulation section 209 modulates transmission data (uplink data) andoutputs a resulting modulated signal to DFT (discrete Fourier transform)section 210.

DFT section 210 transforms the modulated signal inputted from modulationsection 209, to a frequency domain signal, and outputs a plurality ofresulting frequency components to frequency mapping section 211.

Frequency mapping section 211 maps the plurality of frequency componentsinputted from DFT section 210, to PUSCHs allocated to uplink componentbands, according to uplink resource assignment information inputted fromPDCCH receiving section 207.

Here, modulation section 209, DFT section 210 and frequency mappingsection 211 may be provided per component band.

IFFT section 212 transforms the plurality of frequency components mappedto PUSCHs to a time domain waveform, and CP adding section 213 adds a CPto this time-domain waveform.

Transmission RF section 214 is formed with a transmission band which canbe changed, and configures its transmission band, based on bandinformation inputted from configuration information receiving section206. Then, transmission RF section 214 applies transmission radioprocessing (up-conversion, digital-to-analog (D/A) conversion and soforth) to a signal with a CP, and transmits the result via antenna 201.

Next, operations of base station 100 and terminal 200 will be explainedin detail.

In the following descriptions, as shown in FIG. 3, base station 100 andterminal 200 use PDCCHs and PDSCHs allocated to respective downlinkcomponent bands in component band 1 and component band 2 each having acommunication bandwidth of 20 MHz, and PUSCHs allocated to uplinkcomponent bands. In addition, as shown in FIG. 3, one downlink componentband and one uplink component band are associated with one another ineach component band. To be more specific, as shown in FIG. 3, in each ofcomponent bands 1 and 2, one downlink component band including PDCCHsand PDSCHs and one uplink component band including PUSCHs are associatedwith one another. In addition, here, as shown in FIG. 3, in eachdownlink component band, eight PDCCHs (PDCCHs 1 to 8) are used, PDCCHs 1to 4 are used as downlink assignment PDCCHs, which are PDCCHs fordownlink assignment, and PDCCHs 5 to 8 are used as uplink assignmentPDCCHs, which are PDCCHs for uplink assignment.

Configuration section 101 in base station 100 configures uplinkcomponent bands and downlink component bands per terminal. For example,when terminal 200 performs high-speed data communication in both theuplink and the downlink, that is, wideband transmission (that is,transmission in a communication band of 40 MHz), configuration section101 configures two uplink component bands and two downlink componentbands for terminal 200, as shown in FIG. 3. Meanwhile, when terminal 200performs wideband transmission only in the uplink (that is, performsnarrowband transmission in the downlink), configuration section 101configures two uplink component bands and one downlink component band(component band 1) for terminal 200, as shown in FIG. 4. That is, asshown in FIG. 4, while configuration section 101 configures both anuplink component band and a downlink component band in component 1, forterminal 200, configuration section 101 configures only an uplinkcomponent band without configuring (unconfiguring) a downlink componentband in component band 2, for terminal 200. That is, base station 100and terminal 200 perform communication, using two uplink component bandsand one specific downlink component band smaller in number than theuplink component band.

In addition, configuration section 101 configures varying terminal IDsbetween component bands configured for terminal 200. That is, forterminal 200, configuration section 101 configures a plurality ofterminal IDs corresponding to the number of component bands configuredfor terminal 200. For example, as shown in FIG. 3 and FIG. 4,configuration section 101 configures terminal ID # a and terminal ID # bfor component 1 and component band 2 configured for terminal 200,respectively.

Here, component bands for each terminal, which are configured byconfiguration section 101, and respective terminal IDs of componentbands configured for each terminal, are notified to each terminal, usingcontrol channels or PDSCHs. Here, an example of configuration ofterminal IDs will be shown in FIG. 5. In FIG. 5, configuration section101 configures two component bands (component bands 1 and 2) forterminal 1, 2 and 4, and configures one component band (component band1) for terminal 3. In addition, configuration section 101 configuresterminal ID # a and terminal ID # b for component band 1 and componentband 2 configured for terminal 1, respectively. Likewise, configurationsection 101 configures terminal ID # c and terminal ID # d for componentband 1 and component band 2 configured for terminal 2, respectively. Thesame applies to terminal 4. Meanwhile, configuration section 101configures terminal ID # e for component band 1 configured for terminal3. Here, when the number of uplink component bands differs from thenumber of downlink component bands, configuration section 101 configuresterminal IDs, according to the number of component bands configuredmore. For example, when the number of uplink component bands is greaterthan the number of downlink component bands, as in a case in whichwideband transmission is performed only in the uplink, configurationsection 101 configures varying terminal IDs between uplink componentbands.

Next, control section 102 assigns downlink resource assignmentinformation and uplink resource assignment information to PDCCHs in eachcomponent band. For example, as shown in FIG. 3, control section 102assigns downlink resource assignment information indicating assignmentof PDSCHs in component band 1, to PDCCH 1, among downlink assignmentPDCCHs 1 to 4 in component band 1. Meanwhile, control section 102assigns downlink resource assignment information indicating assignmentof PDSCHs in component band 2, to PDCCH 1, among downlink assignmentPDCCHs 1 to 4 in component band 2. The same applies to assignment ofdownlink resource assignment information in FIG. 4.

In addition, as shown in FIG. 3, when wideband transmission is performedin both the uplink and the downlink, control section 102 assigns uplinkresource assignment information indicating assignment of PUSCHs incomponent band 1, to PDCCH 5, among uplink assignment PDCCHs 5 to 8 incomponent band 1. Meanwhile, control section 102 assigns uplink resourceassignment information indicating assignment of PUSCHs in component band2, to PDCCH 5, among uplink assignment PDCCHs 5 to 8 in component band2.

On the other hand, as shown in FIG. 4, when wideband transmission isperformed only in the uplink (when uplink component bands and downlinkcomponent bands are not symmetric), control section 102 assigns uplinkresource assignment information indicating assignment of PUSCHs in theuplink component band associated with an unconfigured downlink componentband (downlink component band in component band 2 in FIG. 4), to PDCCHsin the uplink component band (uplink component band in component band 1in FIG. 4) closest to the unconfigured uplink component band. To be morespecific, as shown in FIG. 4, control section 102 assigns uplinkresource assignment information indicating assignment of PUSCHs incomponent band 2, to PDCCH 6, among uplink assignment PDCCHs 5 to 8 incomponent band 1 neighboring component band 2.

Next, PDCCH generating section 103 masks CRC bits added to resourceassignment information directed to terminal 200, with terminal IDsconfigured on a per component band basis. To be more specific, as shownin FIG. 3, when wideband transmission is performed in both the uplinkand the downlink, PDCCH generating section 103 masks CRC bits added todownlink resource assignment information assigned to PDCCH 1 incomponent band 1 and uplink resource assignment information assigned toPDCCH 5 in component band 1, with terminal ID # a configured forcomponent band 1. Likewise, PDCCH generating section 103 masks CRC bitsadded to downlink resource assignment information assigned to PDCCH 1 incomponent band 2 and uplink resource assignment information assigned toPDCCH 5 in component band 2, with terminal ID # b configured forcomponent band 2.

On the other hand, as shown in FIG. 4, when wideband transmission isperformed only in the uplink, PDCCH generating section 103 masks CRCbits added to downlink resource assignment information about componentband 1 assigned to PDCCH 1 in component band 1, and uplink resourceassignment information about component band 1 assigned to PDCCH 5 incomponent band 1, with terminal ID # a configured for component band 1.Meanwhile, PDCCH generating section 103 masks CRC bits added to uplinkresource assignment information about component band 2, which isassigned to PDCCH 6 in component band 1, with terminal ID # b configuredfor component band 2. That is, PDCCH generating section 103 masks CRCbits added to resource assignment information, with the terminal IDconfigured for a component band targeted for resource assignment, whichis indicated by this resource assignment information.

Configuration information receiving section 206 in terminal 200determines whether terminal 200 performs wideband transmission in boththe uplink and the downlink, or only in the downlink, based onconfiguration information notified from base station 100. In addition,when two downlink component bands are configured in the downlink asshown in FIG. 3, configuration information receiving section 206configures a reception bandwidth of 40 MHz for reception RF section 202,and, when one downlink component band is configured in the downlink asshown in FIG. 4, configures a reception bandwidth of 20 MHz forreception RF section 202. The same applies to transmission bandwidths intransmission RF section 214.

PDCCH receiving section 207 performs blind-decoding on PDCCH signalsallocated to downlink component bands configured for terminal 200, usingterminal IDs configured on a per component band basis. For example, inFIG. 3, downlink component bands in component band 1 and component band2 are configured for terminal 200, as the downlink. Therefore, PDCCHreceiving section 207 determines that PDCCH 1 (downlink resourceassignment information) and PDCCH 5 (uplink resource assignmentinformation) resulting in CRC=OK by demasking PDCCHs 1 to 8 in componentband 1 with terminal ID # a, are PDCCH signals directed to terminal 200in component band 1. In addition, PDCCH receiving section 207 determinesthat PDCCH 1 (downlink resource assignment information) and PDCCH 5(uplink resource assignment information) resulting in CRC=OK bydemasking PDCCHs 1 to 8 in component band 2 with terminal ID # b, arePDCCH signals directed to terminal 200 in component band 2.

On the other hand, in FIG. 4, for terminal 200, only the downlinkcomponent band in component band 1 is configured as the downlink, andthe uplink component bands in component band 1 and component band 2 areconfigured as the uplink. Therefore, PDCCH receiving section 207 demasksPDCCHs 1 to 8 in component band 1, with terminal ID # a, and also withterminal ID # b that is configured for component band 2. Then, PDCCHreceiving section 207 determines that PDCCH 1 (downlink resourceassignment information) and PDCCH 5 (uplink resource assignmentinformation) resulting in CRC=OK by demasking with terminal ID # a, is aPDCCH signal directed to terminal 200 in component band 1. In addition,PDCCH receiving section 207 determines that PDCCH 6 (uplink resourceassignment information) resulting in CRC=OK by demasking with terminalID # b, is a PDCCH signal directed to terminal 200 in component band 2.

As described above, base station 100 configures varying terminal IDsbetween a plurality of component bands configured for terminal 200. Bythis means, in base station 100, varying component bands are configuredbetween uplink component bands, so that PDCCHs resulting from maskinguplink resource assignment information about respective uplink componentbands, with terminal IDs configured on a per uplink component bandbasis. Therefore, base station 100 can notify resource assignmentinformation about the uplink component band associated with anunconfigured downlink component band, using PDCCHs allocated to adifferent component band from the component band including theassociated uplink component band. In addition, terminal 200 can specifywhat uplink component band is indicated by resource allocationinformation assigned to PDCCHs, based on terminal IDs.

Therefore, even if terminal 200 performs wideband transmission only inthe uplink, that is, even if the number of uplink component bandsconfigured for terminal 200 (two, in FIG. 4) is greater than the numberof downlink component bands (one, in FIG. 4), base station 100 cannotify resource assignment information about a plurality of uplinkcomponent bands (respective uplink component bands in component band 1and component band 2 in FIG. 4), using only a specific downlinkcomponent band configured (downlink component band in component band 1in FIG. 4.) That is, terminal 200 can acquire uplink resource assignmentinformation about the uplink component band in component band 2 withoutreceiving PDCCHs in the downlink component band in component band 2shown in FIG. 4. Therefore, even if wideband transmission is performedonly in the uplink, terminal 200 can receive signals in a narrowreception bandwidth (received signals in a communication bandwidth of 20MHz (component band 1) in FIG. 4), and therefore reduce its powerconsumption.

As described above, according to the present embodiment, a base stationconfigures varying terminal IDs between component bands configured foreach terminal. By this means, a terminal can know that resourceassignment information obtained by blind-decoding with a terminal ID isthe resource assignment information about the component band for whichthat terminal ID is configured. Therefore, even if wideband transmissionis performed only in the uplink, that is, even if narrowbandtransmission is performed in the downlink, a terminal can specify uplinkresource assignment information about a plurality of component bands,which is contained in narrowband signals, based on terminal IDs.Consequently, according to the present embodiment, even if widebandtransmission is performed only in the uplink, it is possible to reducepower consumption of terminals.

Moreover, with the present embodiment, even if resources are assigned toa different component band from the component band that is targeted forresource assignment and indicated by resource assignment information, aterminal can specify which uplink component band is indicated by thatresource allocation information, based on terminal IDs. Therefore, withthe present embodiment, like an LTE system, a piece of resourceassignment information contains only resource assignment in onecomponent band (for example, RB assignment of a communication band of 20MHz), so that it is possible to use the same format as in an LTE system.Consequently, according to the present embodiment, a base station doesnot add new information to resource assignment information assigned toPDCCHs, and base stations mask CRC bits of downlink resource assignmentinformation, so that it is possible to perform the same processing as inan LTE system and simplify processing in a base station and terminals.

Embodiment 2

With the present embodiment, a base station configures, for eachterminal, component bands to which PDCCHs to assign resource assignmentinformation directed to each terminal to, are allocated.

Like in Embodiment 1, configuration section 101 (FIG. 1) in base station100 according to the present embodiment configures uplink componentbands and downlink component bands for each terminal, and configurescomponent bands (hereinafter “PDCCH transmission component bands”) towhich PDCCHs to assign resource assignment information directed to eachterminal to, are allocated.

Control section 102 assigns resource assignment information directed toeach terminal, to PDCCHs allocated to PDCCH transmission component bandsconfigured by configuration section 101.

Meanwhile, like in Embodiment 1, configuration information receivingsection 206 (FIG. 2) in terminal 200 according to the present embodimentobtains information about uplink component bands and downlink componentbands configured for terminal 200, and obtains information indicatingPDCCH transmission component bands for terminal 200.

PDCCH receiving section 207 performs blind-decoding on only PDCCHs whichare obtained in configuration information receiving section 206 andallocated to PDCCH transmission component bands for terminal 200.

Next, operations of base station 100 and terminal 200 will be explainedin detail. Like in Embodiment 1 (FIG. 3), a case in which widebandtransmission is performed in both the uplink and the downlink, is shownin FIG. 6, and, like in Embodiment 1 (FIG. 4), a case in which widebandtransmission is performed only in the uplink band (that is, a downlinkcomponent band in component band 2 is unconfigured), is shown in FIG. 7.In addition, in FIG. 6 and FIG. 7, like in Embodiment 1, configurationsection 101 configures terminal ID # a and terminal ID # b for componentband 1 and component band 2 configured for terminal 200, respectively.

For example, in FIG. 6 and FIG. 7, configuration section 101 configurescomponent band 1, as a component band to which PDCCHs to assign resourceassignment information directed to terminal 200 to, are allocated, thatis, as a PDCCH transmission component band for terminal 200.

Then, control section 102 assigns resource assignment informationdirected to terminal 200 in component band 1 and component band 2, toPDCCHs in component band 1, which is a PDCCH transmission componentband. To be more specific, with respect to PDCCHs 1 to 8 in componentband 1, control section 102 assigns downlink resource assignmentinformation about component band 1 to PDCCH 1, downlink resourceassignment information about component band 2 to PDCCH 2, assigns uplinkresource assignment information about component band 1 to PDCCH 5, andassigns uplink resource assignment information about component band 2 toPDCCH 6. In this way, control section 102 assigns both resourceassignment information in component band 1 and component band 2configured for terminal 200, to PDCCHs in component band 1.

Here, as shown in FIG. 6 and FIG. 7, like in Embodiment 1, controlsection 102 masks CRC bits added to resource assignment informationabout component band 1, with terminal ID # a, and masks CRC bits addedto resource assignment information about component 2, with terminal ID #b.

By contrast with this, PDCCH receiving section 207 in terminal 200performs blind-decoding on PDCCH transmission component bands forterminal 200, which are notified from base station 100, that is, PDCCHs1 to 8 in component band 1 shown in FIG. 6 and FIG. 7. As a result ofthis, PDCCH receiving section 207 determines that PDCCHs resulting inCRC=OK by demasking PDCCHs 1 to 8 in component band 1 shown in FIG. 6and FIG. 7 with terminal ID # a, are PDCCH signals directed to terminal200 in component band 1, and determines PDCCHs resulting in CRC=OK bydemasking PDCCHs 1 to 8 in component band 1 by terminal ID # b, arePDCCH signals directed to terminal 200 in component band 2.

Next, FIG. 3 in Embodiment 1 and FIG. 6 in the present embodiment willbe compared. In FIG. 3, sixteen PDCCHs in both component band 1 andcomponent band 2 are targeted for blind-decoding, so that terminal 200performs demodulation, decoding and blind-decoding processing on thesesixteen PDCCHs. By contrast with this, in FIG. 6, only eight PDCCHs incomponent band 1 are targeted for blind-decoding, so that terminal 200performs demodulation, decoding and blind-decoding processing on theseeight PDCCHs, that is, PDCCHs half of these in Embodiment 1.

As described above, resource assignment information directed to terminal200 is assigned to only component band 1 shown in FIG. 6 and FIG. 7, sothat terminal 200 may target only PDCCHs in component band 1 forblind-decoding. That is, terminal 200 can reduce the number of times ofblind-decoding to acquire resource allocation information directed toterminal 200. In addition, as shown in FIG. 7, when widebandtransmission is performed only in the uplink, base station 100 cannotify resource assignment about two uplink component bands, to terminal200, using one downlink component band, like in Embodiment 1.

As described above, according to the present embodiment, it is possibleto produce the same effect as in Embodiment 1, and in addition, whenwideband transmission is performed in both the uplink and the downlink,it is possible to reduce the number of times of blind-decoding in aterminal. Therefore, according to the present embodiment, the number oftimes of blind-decoding is reduced, so that it is possible to realizesimple terminals. In addition, a terminal needs only to store PDCCHs(PDCCHs in component band 1 in FIG. 6 and FIG. 7) to which resourceassignment information directed to the terminal are assigned, in amemory, and therefore can save its memory capacity.

In addition, according to the present embodiment, a base stationconfigures, for each terminal, component bands to which PDCCHs to assignresource assignment information directed to each terminal to, areallocated (that is, PDCCH transmission component bands.) Moreover, abase station configures component bands with high communication qualityas PDCCH transmission component bands, and therefore can reduce a totalof radio resources (e.g. time frequency resources) for PDCCHtransmission. For example, when two component bands belong to twodifferent frequency bands (2 GHz band and 3.4 GHz band), a base stationneeds to transmit PDCCHs only in component bands belonging to a lowerfrequency band, that is, a band of 2 GHz exhibiting smaller propagationloss. By this means, a base station can transmit PDCCHs at a highercoding rate, so that it is possible to reduce radio resources used forPDCCHs.

Embodiment 3

With the present embodiment, only when wideband transmission isperformed only in the uplink, a base station configures varying terminalIDs between uplink component bands configured for each terminal.

In general (for example, in a case in which the uplink and the downlinkare symmetric, or in a case in which wideband transmission is performedonly in the downlink), configuration section 101 (FIG. 1) in basestation 100 in the present embodiment configures one predetermined IDper terminal. On the other hand, in a case in which widebandtransmission is performed only in the uplink (that is, in a case inwhich the number of component bands configured is greater than thenumber of downlink component bands), a configuration section 101 furtherconfigures an additional terminal ID (temporary terminal ID) for aterminal. Here, configuration section 101 generates the number oftemporary terminal IDs equivalent to the difference between the numberof uplink component bands and the number of downlink component bands.Configuration section 101 configures the same number of terminal IDs (apredetermined terminal ID and a temporary terminal ID) as the number ofuplink component bands by adding a temporary terminal ID. By this means,when wideband transmission is performed only in uplink component bands,configuration section 101 configures varying terminal IDs between uplinkcomponent bands, like in Embodiment 1. Configuration section 101 outputsconfiguration information containing the configured temporary terminalID, to PDCCH generating section 103 and modulation section 105. Inaddition, when wideband transmission only in the uplink is not performedagain after adding a terminal ID, configuration section 101 releases atemporary terminal ID.

Here, configuration section 101 generates a temporary terminal IDaccording to a predetermined terminal ID. For example, configurationsection 101 may select any different terminal ID from a predetermined IDas a temporary terminal ID, or may generate a temporary terminal IDbased on a predetermined ID, according to predetermined configurationrules.

PDCCH generating section 103 masks CRC bits added to resource assignmentinformation with terminal IDs contained in configuration informationinputted from configuration section 101. To be more specific, when atemporary terminal ID is not configured, PDCCH generating section 103masks CRC bits using one predetermined terminal ID, in all componentbands configured for a terminal. On the other hand, when a temporaryterminal ID is configured, PDCCH generating section 103 masks CRC bits,using terminal IDs (a predetermined terminal ID and a temporary terminalID) configured on a per uplink component band basis.

By contrast with this, PDCCH receiving section 207 in terminal 200usually performs blind-decoding, using one predetermined terminal IDcontained in configuration information. That is, PDCCH receiving section207 demasks PDCCHs allocated to a downlink component band configured forterminal 200, with a predetermined terminal ID. Meanwhile, when widebandtransmission is performed only in the uplink, PDCCH receiving section207 performs blind-decoding, using a predetermined terminal ID and atemporary terminal ID contained in configuration information.

Next, operations of base station 100 and terminal 200 will be explainedin detail. Like in Embodiment 1 (FIG. 3), a case in which widebandtransmission is performed in both the uplink and downlink, is shown inFIG. 8, and, like in Embodiment 1 (FIG. 4), a case in which widebandtransmission is performed only in the uplink (that is, in a case inwhich the downlink component band in component band 2 is unconfigured),is shown in FIG. 9.

As shown in FIG. 8, configuration section 101 configures terminal ID # afor terminal 200, as a predetermined terminal ID.

Then, as shown in FIG. 8, PDCCH generating section 103 masks, withterminal ID # a, CRC bits of all resource allocation informationassigned to PDCCHs in component band 1 and component band 2 (PDCCH 1 andPDCCH 5 in component band 1 and PDCCH 1 and PDCCH 5 in component band2.)

Therefore, PDCCH receiving section 207 in terminal 200 demasks PDCCHs 1to 8 allocated to component band 1 and component band 2 shown in FIG. 8,with terminal ID # a. To be more specific, PDCCH receiving section 207demasks sixteen PDCCHs composed of PDCCHs 1 to 8 allocated to componentband 1 and component 2 shown in FIG. 8, respectively, with terminal ID #a, and determines that PDCCHs resulting in CRC=OK are PDCCH signalsdirected to terminal 200.

Meanwhile, when wideband transmission is performed only in the uplink asshown in FIG. 9, configuration section 101 adds terminal ID # a toterminal 200, and additionally configures terminal ID # b for terminal200, as a temporary terminal ID. To be more specific, configurationsection 101 configures terminal ID # a for component band 1 configuredin terminal 200, and reconfigures temporary terminal ID # b forcomponent band 2.

Assignment section 102 assigns resource assignment information aboutcomponent band 1 to PDCCH 1 and PDCCH 5 in component band 1, and assignsuplink resource assignment information about component band 2 to PDCCH 6in component band 1.

Then, as shown in FIG. 9, PDCCH generating section 103 masks CRC bits ofresource assignment information about component band 1 assigned to PDCCH1 and PDCCH 5 in component band 1, with terminal ID # a. In addition, asshown in FIG. 9, PDCCH generating section 103 masks CRC bits of uplinkresource assignment information about the downlink component band incomponent band 2, which is assigned to PDCCH 6 in component band 1, withtemporary terminal ID #6.

By contrast with this, like Embodiment 1, PDCCH receiving section 207 interminal 200 demasks PDCCHs 1 to 8 in component band 1 shown in FIG. 9,with terminal ID # b, and determines that PDCCHs resulting in CRC=OK arePDCCH signals directed to terminal 200 in component band 1, and demasksPDCCHs 1 to 8 in component band 1, with terminal ID # b, and determinesthat PDCCHs resulting in CRC=OK are PDCCH signals directed to terminal200 in component band 2.

Next, a sequence diagram showing processing to configure component bandsand terminal IDs is shown in FIG. 10.

In step (hereinafter “ST”) 101, configuration section 101 in basestation 100 configures a terminal ID (for example, terminal ID # a inFIG. 8) for terminal 200, and notifies to the configured terminal ID toterminal 200. In ST 102, configuration section 101 configures uplinkcomponent bands and downlink component bands (for example, as shown inFIG. 8, two uplink component bands and two downlink component bands) forterminal 200 such that the uplink and the downlink are symmetric, andnotifies the configured component bands to terminal 200. Configurationinformation receiving section 206 in terminal 200 configures a receptionbandwidth (two downlink component bands) and a transmission bandwidth(two uplink component bands.) In ST 103, communication (communicationtargeting the uplink and the downlink) is performed between base station100 and terminal 200. At this time, as shown in FIG. 8, in base station100 and terminal 200, uplink and downlink resource assignment incomponent band 1 and component band 2 are performed using PDCCHs maskedwith terminal ID # a.

In ST 104, configuration section 101 in base station 100 reconfigurescomponent bands configured for terminal 200 to perform widebandtransmission only in the uplink, based on the required data transmissionrate or the amount of transmission data in the uplink and the downlink,and notifies the reconfigured component bands to terminal 200. Forexample, configuration section 101 configures two uplink component bandsand one downlink component band for terminal 200, as shown in FIG. 9.Configuration information receiving section 206 configures a receptionbandwidth (one downlink component band) and a transmission bandwidth(two uplink component bands), like in ST 102.

In ST 105, configuration section 101 configures a temporary terminal ID(for example, terminal ID # b in FIG. 9), and notifies the configuredterminal ID to terminal 200. In ST 106, communication (widebandcommunication only in the uplink) is performed between base station 100and terminal 200. At this time, as shown in FIG. 9, in base station 100and terminal 200, uplink resource assignment and downlink resourceassignment in component band 1 are performed, using PDCCHs in componentband 1 masked with terminal ID # a, and uplink resource assignment incomponent band 2 is performed, using PDCCHs in component band 1 maskedwith terminal ID # b.

In ST 107, configuration section 101 in base station 100 reconfigurescomponent bands, for example, like in ST 102, that is, such that theuplink and the downlink are symmetric as shown in FIG. 8, based on therequired data transmission rate or the amount of transmission data inthe uplink and the downlink, and releases the temporary terminal ID(terminal ID # b in FIG. 9) configured in ST 105. Configurationinformation receiving section 206 in terminal 200 configures a receptionbandwidth (two downlink component bands) and a transmission bandwidth(two uplink component bands), like in ST 102. In ST 108, communication(communication targeting the uplink and downlink) is performed betweenbase station 100 and terminal 200.

Here, with Embodiment 1 (FIG. 3 and FIG. 4), varying terminal IDs(terminal ID # a and terminal ID # b) are configured between componentbands configured for each terminal in advance. By contrast with this,with the present embodiment, only when wideband transmission isperformed only in the uplink as shown in FIG. 9, varying terminal IDs(terminal ID # a and temporary terminal ID # b) are configured betweencomponent bands configured for each terminal. That is, as shown in FIG.8, when the uplink and the downlink are symmetric as shown in FIG. 8 (orwhen wideband transmission is performed only in the downlink), onlyterminal ID # a is configured for terminal 200, so that terminal 100 canconfigure, for example, terminal ID # b for another terminal.

As described above, according to the present embodiment, only whenwideband transmission is performed only in the uplink, a base stationconfigures temporary terminal IDs. That is, only when widebandtransmission is performed only in the uplink, a base station configuresvarying terminal IDs between component bands (uplink component bands)for each terminal. Therefore, with the present embodiment, a basestation can minimize terminal IDs used per terminal by additionallyconfiguring a terminal ID (temporary terminal ID) per terminal, so thatit is possible to assign enough terminal IDs to more terminals in asystem.

Embodiment 4

With the present embodiment, only when wideband transmission isperformed only in the uplink, a base station additionally configures atemporary terminal ID for each terminal, like in Embodiment 3.

With the present embodiment, a base station creates a temporary terminalID, according to a predetermined terminal ID configured for eachterminal.

To be more specific, configuration section 101 (FIG. 1) in base station100 according to the present embodiment configures one predeterminedterminal ID for a terminal, like in Embodiment 3. In addition, whenwideband transmission is performed only in the uplink, configurationsection 101 configures a temporary terminal ID created according to apredetermined terminal ID. For example, configuration section 101creates a temporary terminal ID by cyclically shifting (i.e. bitshifting) a predetermined terminal ID.

For example, by regarding a downlink component band to which PDCCHs toassign resource assignment information to, is allocated, as a referencedownlink component band, a relative index indicating how far thedownlink component band associated with an uplink component bandtargeted for resource assignment indicated by uplink resource assignmentinformation, is apart from the reference downlink component band, is thenumber of cyclic shifts. For example, the downlink component band (e.g.component band 1) neighboring a reference downlink component band (e.g.component band 1) is one component band apart from the referencedownlink component band, so that a relative index is 1. Likewise, forexample, when the downlink component band in component band 1 isregarded as a reference downlink component band, for example, thedownlink component band in component band (M+1) is M component bandsapart from the reference downlink component band, so that a relativeindex is M.

Then, as shown in FIG. 11, configuration section 101 creates a temporaryterminal ID by cyclically shifting a predetermined terminal IDconfigured in terminal 200 by a relative index (M in FIG. 11). By thismeans, configuration section 101 configures varying terminal IDs (apredetermined terminal ID and a temporary terminal ID) between aplurality of uplink component bands. Then, PDCCH generating section 103masks a CRC part of resource assignment information composed of apayload part including data in itself and the CRC part including CRCbits, with a temporary terminal ID, as shown in FIG. 11.

Next, for example, as shown in FIG. 12, a case will be explained wherethree uplink component bands (component bands 1 to 3) and one downlinkcomponent band (component band 1) are configured for terminal 200 (FIG.2). That is, in FIG. 12, downlink component bands both in component band1 and component band 2 are unconfigured. In addition, in FIG. 12,predetermined terminal ID # a is configured for terminal 200. Inaddition, in FIG. 12, base station 100 assigns downlink resourceassignment information about component band 1 to PDCCH 1, and assignsuplink resource assignment information about component bands 1 to 3, toPDCCH 5, PDCCH 6 and PDCCH 7, respectively. That is, in FIG. 12, withrespect to component band 1, relative indexes are calculated.

As shown in FIG. 12, base station 100 masks resource assignmentinformation about component band 1, which is assigned to PDCCH 1 andPDCCH 5 in component band 1, with terminal ID # a configured forterminal 200. In addition, the relative index of component band 2 tocomponent band 1 is 1, so that base station 100 masks uplink resourceassignment information about component band 2, which is assigned toPDCCH 6 in component band 1, with temporary terminal ID # a (+1)obtained by cyclically shifting uplink resource assignment informationabout component band 2 by relative index (1), as shown in FIG. 12.Likewise, the relative index of component band 3 to component band 1 is2, so that base station 100 masks uplink resource assignment informationabout component band 3, which is assigned to PDCCH 7 in component band1, with temporary terminal ID # a (+2) obtained by cyclically shiftingterminal ID # a by relative index (2), as shown in FIG. 12.

Meanwhile, when wideband transmission is performed only in the uplink,terminal 200 creates a terminal ID (temporary terminal ID) for eachcomponent band, according to a predetermined terminal ID (terminal ID #a in FIG. 12) configured for terminal 200, like base station 100. Bythis means, base station 100 does not need to notify a temporaryterminal ID to terminal 200. In addition, configuration section 101calculates a relative index to a reference component band and creates aterminal ID obtained by cyclically shifting a predetermined terminal IDby the relative index, so that base station 100 does not need to notifyassociations between component bands and terminal IDs. That is, basestation 100 needs only to notify only a predetermined terminal ID toterminal 200 as a notification related to terminal IDs.

In addition, terminal 200 needs only to specify relative indexes betweencomponent bands configured for terminal 200, and does not need to knowthe total number of component bands in the system and absolute componentband numbers, so that it is possible to reduce the amount of controlinformation required to notify terminal IDs from base station 100 toterminal 200.

As described above, according to the present embodiment, it is possibleto produce the same effect as in Embodiment 3, and moreover, it is notnecessary to notify temporary terminal IDs from a base station toterminals, so that it is possible to reduce the amount of controlinformation. Moreover, according to the present embodiment, a basestation creates a terminal ID obtained by cyclically shifting a terminalID configured for a reference component band by a relative index, sothat it is possible to use any component band as a reference componentband. Accordingly, a base station can notify resource assignmentinformation about a plurality of uplink component bands, even fromPDCCHs allocated to downlink component bands in any component bands.

Here, with the present embodiment, a case has been explained where abase station creates a temporary terminal ID by cyclically shifting apredetermined terminal ID by a relative index. However, according to thepresent invention, a base station may cyclically shift a CRC part addedto resource assignment information by a relative index, and mask a CRCpart (CRC bits) after cyclic shift, with a predetermined terminal ID.Alternatively, a base station may mask a CRC part with a predeterminedterminal ID and cyclically shift a CRC part after masking by a relativeindex. In this case, it is possible to produce the same effect as in thepresent embodiment.

In addition, with the present embodiment, although a case has beenexplained where a base station creates a temporary terminal ID bycyclically shifting a predetermined terminal ID by a relative index, abase station may create a temporary terminal ID by adding a relativeindex to a predetermined terminal ID, according to the presentinvention.

Embodiment 5

With the present embodiment, a base station configures varying searchspaces between component bands configured for each terminal.

Each PDCCH is transmitted per resource or every a plurality ofresources, where a resource is referred to as “CCE (control channelelement)”. In addition, in order to reduce the number of times ofblind-decoding in a terminal, LTE are studying a method for limiting CCEregions (search spaces), which are CCEs targeted for blind-decoding, ona per terminal basis. A base station assigns resource assignmentinformation to PDCCHs in a search space assigned to a terminal, which isthe destination of the resource assignment information, and the terminalperforms blind-decoding on only the PDCCHs in the search space assignedto the terminal.

With the present embodiment, a base station configures varying searchspaces between component bands configured for each terminal, and eachterminal specifies resource assignment information per component band byperforming blind-decoding on a search space per component band.

Configuration section 101 (FIG. 1) in base station 100 according to thepresent embodiment configures varying search spaces between a pluralityof component bands configured for each terminal. For example, as shownin FIG. 13, when wideband transmission is performed in both the uplinkand the downlink, configuration section 101 configures PDCCHs 1 to 4 fordownlink component bands in component band 1, as a search space incomponent band 1 (search space for assignment of component band 1.) Inaddition, configuration section 101 configures PDCCHs 5 to 8 fordownlink component bands in component band 2, as a search space incomponent band 2 (search space for assignment of component band 2.)

On the other hand, for example, as shown in FIG. 14, when widebandtransmission is performed only in the uplink (that is, when componentband 2 is unconfigured), configuration section 101 configures PDCCHs 1to 4 in the downlink component band in component band 1 as a searchspace for assignment of component band 1, and configures PDCCHs 5 to 8in the downlink component band in component band 1 as a search space forassignment of component band 2.

Control section 102 assigns uplink resource assignment information anddownlink resource assignment information to PDCCHs in a search spaceconfigured for each terminal, based on information related to searchspaces indicated by configuration information inputted fromconfiguration section 101. For example, in FIG. 13 and FIG. 14, controlsection 102 assigns resource assignment information about component band1 to any of PDCCHs 1 to 4 (in component band 1) in the search space forassignment of component 1 shown in FIG. 13 and FIG. 14. In addition,control section 102 assigns resource assignment information aboutcomponent band 2 to PDCCHs 5 to 8 (in component band 2) in the searchspace for assignment of component band 2 shown in FIG. 13 and FIG. 14.

Here, configuration section 101 configures one terminal ID for eachterminal. Therefore, PDCCH generating section 103 masks CRC bits addedto resource assignment information directed to each terminal, with theterminal ID configured for each terminal, independent of componentbands.

PDCCH receiving section 207 (FIG. 2) in terminal 200 performsblind-decoding on only PDCCHs in search spaces configured for terminal200. To be more specific, PDCCH receiving section 207 obtains resourceassignment information in component band 1 directed to terminal 200 byperforming blind-decoding on only PDCCHs 1 to 4 in the search space forassignment of component band 1 shown in FIG. 13 and FIG. 14. Likewise,PDCCH receiving section 207 obtains resource assignment information incomponent band 2 directed to terminal 200 by performing blind-decodingon only PDCCHs 5 to 8 (in component band 2) in the search space forassignment of component band 2 shown in FIG. 13, or PDCCHs 5 to 8 (incomponent band 1) in the search space for assignment of component band 2shown in FIG. 14.

As described above, according to the present embodiment, a base stationconfigures varying search spaces between component bands configured foreach terminal. By this means, even if wideband transmission is performedonly in the uplink, a base station can assign uplink resource assignmentinformation about different component bands, to different search spacesin one downlink component band. Therefore, each terminal can specifyresource assignment information for each component band by performingblind-decoding on only a search space per component band. Consequently,according to the present embodiment, it is possible to produce the sameeffect as in Embodiment 1.

That is, when wideband transmission is performed only in the uplink, inother wards, when narrowband transmission is performed in the downlink,each terminal can specify uplink resource assignment information about aplurality of component bands, which is contained in narrow band signals,based on search spaces. Therefore, according to the present embodiment,even if wideband transmission is performed only in the uplink, it ispossible to reduce power consumption of terminals. Moreover, with thepresent embodiment, even if resources are assigned to a differentcomponent band from a component band targeted for resource assignmentindicated by resource assignment information, terminals can specify whatuplink component band is indicated by that resource assignmentinformation, based on search spaces. Therefore, with the presentembodiment, like an LTE system, one piece of resource assignmentinformation contains only resource assignment (for example, RBassignment in a communication band of 20 MHz) in one component band, sothat it is possible to use the same format as in an LTE system.Consequently, according to the present embodiment, a base station doesnot add new information to resource assignment information assigned toPDCCHs, and terminals specify search spaces to transmit PDCCHs, so thatit is possible to perform the same processing as in an LTE system andsimplify processing in a base station and terminals.

Here, with the present embodiment, a case has been explained where abase station configures varying search spaces according to componentbands targeted for assignment, for PDCCHs used for assignment of uplinkcomponent bands. However, according to the present invention, when aplurality of downlink component bands are configured, a base station maysimilarly configure varying search spaces according to component bandstargeted for assignment, for PDCCHs used for assignment of downlinkcomponent bands. In this case, it is possible to share processingbetween the uplink and the downlink to allow simplification ofterminals.

Each embodiment of the present invention has been explained.

Here, in the present invention, for example, as shown in FIG. 15, whenthree uplink component bands and two downlink component bands areconfigured, that is, when a smaller number of downlink component bandsthan the number of uplink component bands are configured, there are aplurality of component bands to assign resource assignment informationto. To be more specific, in FIG. 15, PDCCHs in the downlink componentbands in both component band 1 and component band 2 are used to notifyresource assignment information. Here, with the above-describedembodiments, a case has been explained where the component band(downlink component band in component band 2 in FIG. 15) closest to theunconfigured downlink component band (downlink component band incomponent band 3 in FIG. 15) is used to notify resource assignmentinformation about the uplink component band associated with theunconfigured component band. However, according to the presentinvention, component bands used to notify resource assignmentinformation about the uplink component band associated with anunconfigured downlink component band may be assigned evenly to usablecomponent bands (component band 1 and component band 2 in FIG. 15.) Bythis means, it is possible to prevent resource assignment informationfrom being assigned to only a specific component band. Alternatively, itmay be determined in advance what component band is used to notifyresource assignment information. For example, component bands may bedetermined according to low-order bits of the terminal ID configured foreach terminal. By this means, component bands to assign resourceassignment information to, are distributed, so that it is possible toprevent resource assignment information from being assigned to only aspecific component band.

In addition, in the present invention, C-RNTIs (cell-radio networktemporary identifiers) may be used as terminal IDs.

Moreover, with the above-described embodiments, a case has beendescribed where a base station masks (scrambles) CRC bits added tocontrol information, with terminal IDs. However, according to thepresent invention, CRC bits may be masked (scrambled) with, notexclusively terminal IDs, varying sequences between component bands, orsequences obtained by multiplying terminal IDs by sequences varyingbetween component bands, respectively. Here, it is possible to performthe same PDCCH generation processing (or PDCCH reception processing) asin an LTE system by using terminal IDs for masking (scrambling) CRCbits. Here, when sequences other than terminal IDs are used for masking(scrambling) CRC bits, additional masking (scrambling) processing isrequired, but the amount of additional processing is not large enough toinfluence the system, so that it is possible to construct simple basestation and terminals, like the above-described embodiments.

In addition, with the above-described embodiments, although a case hasbeen described where a base station applies masking (scrambling)processing to CRC bits (for example, the CRC part shown in FIG. 11), abase station may apply masking (scrambling) processing to a payload part(for example, the payload part shown in FIG. 11), according to thepresent invention. In this case, as compared to LTE, although masking(scrambling) processing on a payload part increases, the size of thepayload part is short, dozens of bits, so that processing load interminals increases little. In addition, in this case, it is possible touse the same PDCCHs as in LTE, so that it is possible to constructsimple base station and terminals.

In the present invention, masking (scrambling) processing may be bit bybit (that is, CRC bit by terminal ID) multiplication, or a bit and a bitmay be added and this adding result may be used to calculate mod 2 (thatis, the remainder resulting from dividing the adding result by 2.)

In addition, with the above-described embodiments, a case has beenexplained where, for PDCCHs to assign uplink data transmitted in anuplink component band, a base station masks CRC bits with the terminalID matching the uplink component band. However, according to the presentinvention, when a plurality of downlink component bands are configured,a base station may mask, also for PDCCHs to assign downlink datatransmitted in a downlink component band, CRC bits with the terminal IDmatching the downlink component band, like uplink component bands. Bythis means, it is possible to share processing between the uplink andthe downlink to allow simplification of terminals.

In addition, with the above-described embodiments, a case has beenexplained where a component band is defined as a band having the maximumwidth of 20 MHz and a basic unit of communication band. However, acomponent band may be defined as follows. For example, a downlinkcomponent band may be defined as a band segmented by downlink frequencyband information in a BCH (broadcast channel) notified from a basestation, or a band defined by a distribution width in a case in whichPDCCHs are distributed and allocated in the frequency domain. Inaddition, an uplink may be defined as a band segmented by uplinkfrequency band information in a BCH notified from a base station, or abasic unit of communication band equal to or lower than 20 MHz includingPUSCH near the center and PUCCHs (physical uplink control channels) atboth ends.

Moreover, although a case has been explained where the communicationbandwidth of a component band is 20 MHz, the communication bandwidth ofa component band is not limited to 20 MHz.

Furthermore, resource assignment information transmitted on PDCCHs mayalso be referred to as “DCI (downlink control information)”.

In addition, band aggregation may also be referred to as “carrieraggregation.” Moreover, a component band may also be referred to as“component carrier.” Furthermore, band aggregation is not limited to acase in which consecutive frequency bands are connected, butdiscontinuous frequency bands may be connected.

In addition, a terminal may also be referred to as “UE”, and a basestation may also be “Node B” or “BS (base station)”. Moreover, aterminal ID may also be referred to as “UE-ID.”

Also, although cases have been described with the above embodiment asexamples where the present invention is configured by hardware, thepresent invention can also be realized by software.

Each function block employed in the description of each of theaforementioned embodiments may typically be implemented as an LSIconstituted by an integrated circuit. These may be individual chips orpartially or totally contained on a single chip. “LSI” is adopted herebut this may also be referred to as “IC,” “system LSI,” “super LSI,” or“ultra LSI” depending on differing extents of integration.

Further, the method of circuit integration is not limited to LSI's, andimplementation using dedicated circuitry or general purpose processorsis also possible. After LSI manufacture, utilization of a programmableFPGA (Field Programmable Gate Array) or a reconfigurable processor whereconnections and settings of circuit cells within an LSI can bereconfigured is also possible.

Further, if integrated circuit technology comes out to replace LSI's asa result of the advancement of semiconductor technology or a derivativeother technology, it is naturally also possible to carry out functionblock integration using this technology. Application of biotechnology isalso possible.

The disclosure of Japanese Patent Application No. 2008-207369, filed onAug. 11, 2008, including the specification, drawings and abstract, isincorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a mobile communication system andso forth.

The invention claimed is:
 1. A communication device comprising:circuitry, which, in operation, maps first control information, whichincludes resource assignment information indicating a first resourceallocated to a terminal in a first component carrier (CC) out ofmultiple CCs configured for the terminal, on a first search spacespecific to the first CC and maps second control information, whichincludes resource assignment information indicating a second resourceallocated to the terminal in a second CC out of the multiple CCs, on asecond search space specific to the second CC, the first controlinformation and the second control information being mapped on one outof the multiple CCs; and a transmitter, which, in operation, transmitsthe first control information and the second control information to theterminal.
 2. The communication device according to claim 1, wherein thefirst control information includes information indicating the first CC,and the second control information includes information indicating thesecond CC.
 3. The communication device according to claim 1, wherein thefirst CC and the second CC have frequencies different from each other.4. The communication device according to claim 1, wherein a CRCscrambled by a terminal ID is attached for each of the first controlinformation and the second control information.
 5. The communicationdevice according to claim 1, wherein the first search space is definedby a plurality of control channel elements that are specific to thefirst CC, and the second search space is defined by a plurality ofcontrol channel elements that are specific to the second CC.
 6. Thecommunication device according to claim 1, wherein at least one of thefirst control information and the second control information includesthe resource assignment information indicating an uplink resourceallocated to the terminal, and said communication device comprises areceiver, which, in operation, receives data based on the resourceassignment information.
 7. The communication device according to claim1, wherein at least one of the first control information and the secondcontrol information includes the resource assignment informationindicating a downlink resource allocated to the communication device,and said transmitter, in operation, transmits data based on the resourceassignment information.
 8. A communication device comprising: circuitry,which, in operation, maps a plurality of control information, each ofwhich includes resource assignment information indicating a resourceallocated to a terminal in respective one of a plurality of componentcarriers (CCs) configured for the terminal, on one out of the pluralityof CCs, each of the plurality of control information being mapped on asearch space specific to the respective one of the plurality of CCs; anda transmitter, which, in operation, transmits the plurality of controlinformation on one out of the plurality of CCs to the terminal.
 9. Thecommunication device according to claim 8, wherein each of the pluralityof control information includes information indicating the respectiveone of the plurality of CCs.
 10. The communication device according toclaim 8, wherein the plurality of CCs have frequencies different fromeach other.
 11. A communication method comprising: mapping first controlinformation, which includes resource assignment information indicating afirst resource allocated to a terminal in a first component carrier (CC)out of multiple CCs configured for the terminal, on a first search spacespecific to the first CC; mapping second control information, whichincludes resource assignment information indicating a second resourceallocated to the terminal in a second CC out of the multiple CCs, on asecond search space specific to the second CC, the first controlinformation and the second control information being mapped on one outof the multiple CCs; and transmitting the first control information andthe second control information to the terminal.
 12. The communicationmethod according to claim 11, wherein the first control informationincludes information indicating the first CC, and the second controlinformation includes information indicating the second CC.
 13. Thecommunication method according to claim 11, wherein the first CC and thesecond CC have frequencies different from each other.
 14. Thecommunication method according to claim 11, wherein a CRC scrambled by aterminal ID is attached for each of the first control information andthe second control information.
 15. The communication method accordingto claim 11, wherein the first search space is defined by a plurality ofcontrol channel elements that are specific to the first CC, and thesecond search space is defined by a plurality of control channelelements that are specific to the second CC.
 16. The communicationmethod according to claim 11, wherein at least one of the first controlinformation and the second control information includes the resourceassignment information indicating an uplink resource allocated to theterminal, and said communication method comprises receiving data basedon the resource assignment information.
 17. The communication methodaccording to claim 11, wherein at least one of the first controlinformation and the second control information includes the resourceassignment information indicating a downlink resource allocated to thecommunication device, and said communication method comprisestransmitting data based on the resource assignment information.
 18. Acommunication method comprising: mapping a plurality of controlinformation, each of which includes resource assignment informationindicating a resource allocated to a terminal in respective one of aplurality of component carriers (CCs) configured for the terminal, onone out of the plurality of CCs, each of the plurality of controlinformation being mapped on a search space specific to the respectiveone of the plurality of CCs; and transmitting the plurality of controlinformation on one out of the plurality of CCs to the terminal.
 19. Thecommunication method according to claim 18, wherein each of theplurality of control information includes information indicating therespective one of the plurality of CCs.
 20. The communication methodaccording to claim 18, wherein the plurality of CCs have frequenciesdifferent from each other.